From
Adrian's Rojak Pot's "The Definitive BIOS Optimization Guide" -
"Setting the PNP OS Installed feature to No allows the BIOS to configure all devices under the assumption that the operating system cannot do so. Therefore, all hardware settings are fixed by the BIOS at boot up and will not be changed by the operating system.
Setting the feature to Yes, the BIOS will only configure critical devices like the graphics card and hard disk. The other motherboard devices are then configured by the operating system. This allows the operating system some flexibility in shuffling system resources like IRQs and IO ports to avoid conflicts. It also gives you some degree of freedom in manually shuffling system resources."
Without the seemingly troublesome cards installed, do you have any resources free (IRQ's, etc...)?? Maybe setting this feature to "on" may help you out... You can always turn it off if it doesn't...
I'm assuming you are trying to add "something" to the computer to connect all your networking stuff, and it doesn't really matter what (does it?) I'm not sure why installing the NIC kills the system, unless it is a bad card, or it can't find the resources it needs to work right. As for the USB-2 cards, I bought an Adaptec Duo-Connect (USB-1, USB-2, and IEEE 1394 all-in-one) and had no troubles installing that into my machine, including the Adaptec USB-2 driver, even though I don't have any USB-2 devices as yet. I did that to save a PCI slot, and has worked out fine. What do you have that requires USB-2? I assume the Wireless Adapter plugs into your motherboards existing USB-1 ports...correct? That may be a whole different problem as to why it crashes IE or Netscape. I have seen the IE message before...what does the error printout say (you don't have to send it to Microsoft to read the error text, though I don't recall how at this moment)...might give you some more insight on the problem...